<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="./css/bootstrap.css">
    <title>Document</title>
</head>
<body>
    <img src="./img/渐变图片.png" alt="图片未能显示" class="img-responsive">
    <hr>
    <!-- 圆形 -->
    <img src="./img/渐变图片.png" alt="图片未能显示" class="img-responsive img-circle">
    <!-- 圆角 -->
    <img src="./img/渐变图片.png" alt="图片未能显示" class="img-responsive img-rounded">
    <!-- 双线 -->
    <img src="./img/渐变图片.png" alt="图片未能显示" class="img-responsive img-thumbnail">

</body>
</html>